Learning curve for lateral meniscal allograft transplantation: preventing meniscal extrusion

Abstract Purpose This study analyzes the large number of lateral meniscal allograft transplantation (LMAT) procedures conducted by a single surgeon over 23 years in order to determine whether the absolute amount of graft subluxation and the incidence of extrusion are different at the present time compared to the early MAT era. Methods We reviewed 320 cases of lateral MAT performed by a single surgeon between 1996 and 2019. This cohort was chronologically divided into eight groups (eight groups of 40). The absolute amount of subluxation was measured by the coronal sections of magnetic resonance images taken one-year post-operation. Subluxation by more than 3 mm was considered as extrusion. The graft extrusion learning curve was plotted in each series using the learning curve cumulative summation test (LC-CUSUM). Results Extrusion incidence was 41.6%, and the mean absolute amount of graft subluxation was 3.4 ± 2.2 mm for all subjects. There were significant between-group differences in extrusion incidence and absolute amount of graft subluxation (extrusion incidence, P Conclusion The incidence of extrusion and absolute amount of graft subluxation decreased significantly over a period of 23 years, and the surgeon achieved a certain level of proficiency after 128 cases.